| publications-4061 |
article |
2006 |
Dawsey, Wesley J. and Minsker, Barbara S. and VanBlaricum, Vicki |
Bayesian Belief Networks to Integrate Monitoring Evidence of Water Distribution System Contamination |
Journal of Water Resources Planning and Management |
10.1061/(asce)0733-9496(2006)132:4(234) |
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A Bayesian belief network (BBN) methodology is proposed for combining evidence to better characterize contamination events and reduce false positive sensor detections in drinking water distribution systems. A BBN is developed that integrates sensor data with other validating evidence of contamination scenarios. This network is used to graphically express the causal relationships between events such as operational changes or a true contaminant release and consequent observable evidence in an example distribution system. In the BBN methodology proposed here, multiple computer simulations of contaminant transport are used to estimate the prior probabilities of a positive sensor detection. These simulations are run over multiple combinations of possible source locations and initial mass injections for a conservative solute. This approach provides insight into the effect of uncertainties in source mass and location on the detection probability of the sensors. In addition, the simulations identify the upstream ... |
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| publications-4062 |
article |
2013 |
Nardo, Armando Di and Nardo, Armando Di and Natale, Michele Di and Natale, Michele Di and Guida, Mario and Guida, Mario and Musmarra, Dino and Musmarra, Dino |
Water Network Protection from Intentional Contamination by Sectorization |
Water Resources Management |
10.1007/s11269-012-0133-y |
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Each single phase of a water supply network, from water adduction to distribution to end-users, is exposed to many diverse potential sources of intentional contamination (or malicious attacks). One of the most dangerous threats is a backflow attack that occurs when a pump system, easily available on the market, is utilized to overcome the pressure gradient of network pipes. In this work, a simple backflow attack with cyanide being introduced into a real-water system is modeled and the most dangerous introduction points for a contaminant incident are defined. Moreover, the network vulnerability has been analyzed by computing the lethal dose of cyanide ingested by users and the total length of the contaminated water system. Eventually the effects of network partitioning and district isolation to protect water supply systems have been investigated. The results show how district closing - by network sectorization techniques used to improve leakage search and reduction - can significantly decrease contaminant diffusion and protect part of the users from cyanide uptake. Network sectorization can also reduce the risk of simple malicious attacks because several introduction points are necessary to have a massive negative impact on the network. Simulation results also show that in some cases water network partitioning may worsen water network protection and further studies are necessary to design water districts for network security and safety. Copyright Springer Science+Business Media B.V. 2013 |
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| publications-4063 |
article |
2012 |
Xin, Kunlun and Xin, Kunlun and Xin, Kunlun and Tao, Tao and Tao, Tao and Tao, Tao and Tao, Tao and Wang, Yong and Wang, Yong and Liu, Suiqing and Liu, Suiqing and Liu, Suiqing |
Hazard and vulnerability evaluation of water distribution system in cases of contamination intrusion accidents |
Frontiers of Environmental Science & Engineering in China |
10.1007/s11783-012-0409-8 |
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In this paper, it proposed an index system for hazard and vulnerability evaluations of water distribution networks, based on the simulation of contamination events caused by pollutant injections at different junctions. It attempted to answer the following two questions in the case of contamination events: 1) Which are the most hazardous junctions? 2) Which are the most vulnerable junctions? With EPANET toolkit, it simulated the propagation of the contaminant, and calculated the peak concentration of the contaminant and mass delivered at different nodes. According to types of consumers, different weights were assigned to the consumer nodes for assessing the influence of the contaminant on the consumers. Using the method proposed herein, both the hazard index and vulnerability index were calculated for each node in the pipe network. The presented method was therefore applied to the water network of the city of Zhenjiang, which contains two water plants, two booster pump stations with storage tanks. In conclusion, the response time, the relationships between the peak concentration of contaminant and the total absorption are the most important factors in hazard and vulnerability evaluation of the water distribution network. |
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| publications-4064 |
article |
2010 |
Poulin, Annie and Mailhot, Alain and Periche, Nathalie and Delorme, Louis and Villeneuve, Jean-Pierre |
Planning Unidirectional Flushing Operations as a Response to Drinking Water Distribution System Contamination |
Journal of Water Resources Planning and Management |
10.1061/(asce)wr.1943-5452.0000085 |
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This paper addresses the issue of contaminated water evacuation as part of the response process in cases of intentional or accidental contamination of drinking water distribution systems (DWDSs). Following a previous study which addressed contaminant isolation, an original flushing procedure (FP) is introduced. Through a heuristic set of rules, the FP defines unidirectional flushing (UDF) strategies in a safe, structured, and efficient manner. In addition to the rather theoretical considerations related to hydraulics modeling, the FP also takes into account the operational issues of UDF implementation. Compared to other similar studies, the latter aspect establishes the main contribution of this paper. The FP has been applied to two real-world networks and application of the heuristic rules is demonstrated with the aid of a detailed example. General results suggest possible improvements to existing network configurations and to the design of projected networks to better support contamination response plan... |
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| publications-4065 |
article |
2011 |
Farwell, James P. and Farwell, James P. and Rohozinski, Rafal and Rohozinski, Rafal and Rohozinski, Rafal |
Stuxnet and the Future of Cyber War |
Survival |
10.1080/00396338.2011.555586 |
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The discovery in June 2010 that a cyber worm dubbed β€Stuxnet’ had struck the Iranian nuclear facility at Natanz suggested that, for cyber war, the future is now. Yet more important is the political and strategic context in which new cyber threats are emerging, and the effects the worm has generated in this respect. Perhaps most striking is the confluence between cyber crime and state action. States are capitalising on technology whose development is driven by cyber crime, and perhaps outsourcing cyber attacks to non-attributable third parties, including criminal organisations. Cyber offers great potential for striking at enemies with less risk than using traditional military means. It is unclear how much the Stuxnet program cost, but it was almost certainly less than the cost of single fighter-bomber. Yet if damage from cyber attacks can be quickly repaired, careful strategic thought is required in comparing the cost and benefits of cyber versus traditional military attack. One important benefit of cyber ... |
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| publications-4066 |
article |
2008 |
Poulin, Annie and Mailhot, Alain and Grondin, Patrice and Delorme, Louis and Periche, Nathalie and Villeneuve, Jean-Pierre |
Heuristic Approach for Operational Response to Drinking Water Contamination |
Journal of Water Resources Planning and Management |
10.1061/(asce)0733-9496(2008)134:5(457) |
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This paper introduces a simple topological approach to systematize the isolation of contaminated areas within the pressure zones of drinking water distribution systems (DWDSs). Assuming optimal location of contaminant detectors and known flow conditions, a heuristic procedure delineates the area to be isolated and identifies the valves to be closed by response teams sent in the field, taking into account a response delay from the time of first detection. As a first step leading to the development of a more comprehensive algorithmic application, the approach was elaborated and validated from a pragmatic perspective using two real-world DWDSs. Depending on each network’s design, configuration, and assumed flow conditions, application of the isolation procedure will result in different isolation strategies (extent of isolated areas, number of required isolation valves). The current approach is based on a set of simplifying assumptions, and needs to be further validated with other networks. The proposed metho... |
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| publications-4067 |
article |
2008 |
Skolicki, Zbigniew and Skolicki, Zbigniew and Arciszewski, Tomasz and Arciszewski, Tomasz and Houck, Mark H. and Houck, M. H. and Houck, Mark H. and Jong, Kenneth De and Jong, K. De |
Co-evolution of terrorist and security scenarios for water distribution systems |
Advances in Engineering Software |
10.1016/j.advengsoft.2008.04.001 |
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| publications-4068 |
article |
2014 |
Donkor, Emmanuel A. and Donkor, Emmanuel A. and Donkor, Emmanuel and Mazzuchi, Thomas A. and Mazzuchi, Thomas A. and Soyer, Refik and Soyer, Refik and Roberson, J. Alan and Roberson, J. Alan and Roberson, J. Alan |
Urban Water Demand Forecasting: Review of Methods and Models |
Journal of Water Resources Planning and Management |
10.1061/(asce)wr.1943-5452.0000314 |
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AbstractThis paper reviews the literature on urban water demand forecasting published from 2000 to 2010 to identify methods and models useful for specific water utility decision making problems. Results show that although a wide variety of methods and models have attracted attention, applications of these models differ, depending on the forecast variable, its periodicity and the forecast horizon. Whereas artificial neural networks are more likely to be used for short-term forecasting, econometric models, coupled with simulation or scenario-based forecasting, tend to be used for long-term strategic decisions. Much more attention needs to be given to probabilistic forecasting methods if utilities are to make decisions that reflect the level of uncertainty in future demand forecasts. |
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| publications-4069 |
article |
2014 |
Shuang, Qing and Shuang, Qing and Zhang, Mingyuan and Zhang, Mingyuan and Yuan, Yunhao and Yuan, Yongbo |
Node vulnerability of water distribution networks under cascading failures |
Reliability Engineering & System Safety |
10.1016/j.ress.2013.12.002 |
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| publications-4070 |
article |
2005 |
Zhang, Pengcheng and Zhang, Pengcheng and Peeta, Srinivas and Peeta, Srinivas and Friesz, Terry L. and Friesz, Terry L. |
Dynamic Game Theoretic Model of Multi-Layer Infrastructure Networks |
Networks and Spatial Economics |
10.1007/s11067-005-2627-0 |
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Due to similarities in terms of network structure and interactions among them, most infrastructure systems can be viewed as coupled layers of a generalized transportation network in which the passenger, freight, data, water, and energy flows are the commodities in the different layers. The coupling is due to the varying degrees of interactions among these layers in terms of shared physical networks, budgetary constraints, socio-economic environments, environmental concerns, information/other resources, and in particular, functional interdependencies. However, these interactions are normally ignored in the engineering planning, design and analysis of infrastructure systems. Identifying and understanding these interactions using a holistic perspective can lead to more efficient infrastructure systems. This paper presents a preliminary network flow equilibrium model of dynamic multi-layer infrastructure networks in the form of a differential game involving two essential time scales. In particular, three coupled network layersβ€”automobiles, urban freight and dataβ€”are modeled as being comprised of Cournot-Nash dynamic agents. An agent-based simulation solution structure is introduced to solve the flow equilibrium and optimal budget allocation problem for these three layers under the assumption of a super authority that oversees investments in the infrastructure of all three technologies and thereby creates a dynamic Stackelberg leader-follower game. |
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